Are there caveat's to a Personal Record (PR)

I ran my fastest marathon twenty years ago. There is not much of a chance that I will ever be that fast for that long again. I ran my fastest half marathon over twenty years ago. A few years back I gave it a serious challenge but was still over a full minute slower per mile than my PR. The same could be said for almost every race distance I have done. Although at Pat's Run, I did set a PR of 29:52 at the 4.2 mile race (7:06) simply because I had never raced that specific distance before. 

That's the rub, isn't it. After hundreds of races at distances from 1 mile to 140.6 miles, the only PR I can claim today can come from a distance I haven't done under the clock already. Although I suppose I could beat my 8k race time of 40 minutes because I have only done that event distance once a long time ago.

Do I have to live in the shadow of my twenty year old self? Couldn't I, or can I, start telling people I PR'd because I aged up, or I came back from a 'never race again' injury? It would certainly make my race reports more interesting. We live in a bite sized, sound bite world now. I could write a thousand words on the what, when, where and how I did at a race but nothing is as sensational or would receive as much response as writing, "I got a PR at X event this weekend". 

There is some sense to making the claim that I PR'd a distance based on my age and not over my lifetime. I might not be as fast as I was two decades ago, but if I regularly run half marathons or 10ks over the course of my 30's, I can show a PR based on that decade. 

I think most of use us this way of thinking already. If I during my 30's, a course of ten years and two age groups, I raced fifty 10k runs and can show that my fastest time at the distance was when I was 38, can't I say I had a PR for 10ks while I was in that age group, or for that decade in my life. I'd like to think so. 

Till then I will live in the glory of my youth or the advantage of a ridiculously easily race course.